Simsima eSIM Data Plans for Japan

Simsima does not provide a truly unlimited high‑speed eSIM plan for Japan. The plans that carry the word “Unlimited” in their name—such as Japan Unlimited 7Days, Unlimited – 7 days, Japan Unlimited 10Days, Unlimited – 10 days, Japan Unlimited 30Days, and Unlimited – 30 days—actually offer 3GB of high‑speed data per day and then throttle the connection to 1 Mbps after that daily limit is reached.

Instead, Simsima offers fixed data plans with larger allowances, for example 100GB for 180 days or 50GB for 30 days, both delivered at 5G speed throughout the validity period. These fixed plans can be more cost‑effective for travelers who need a substantial amount of data, while users who consume data far beyond the caps can still top up as needed.

Simsima does not provide a phone number or SMS capability on its Japan eSIM plans; only data‑only plans are available. Travelers can still use VoIP applications such as WhatsApp, Telegram, and iMessage over the data connection for calls and messaging, but they should check that these services are accessible in Japan before purchasing.

Simsima provides 14 single‑country plans and 21 multi‑country plans for use in Japan. The available plans span a price range from roughly $1.50 to $178.48, with data limits that vary from 100 MB up to 100 GB. The validity of these plans can last anywhere from 5 days to a full year, allowing travelers to choose options that best fit their stay length and data needs.